code: def _handle_headers(
      headers: Optional[str],
  ) -> Optional[Dict[str, Any]]:
      if headers is None and "RAY_JOB_HEADERS" in os.environ:
          headers = os.environ["RAY_JOB_HEADERS"]
      if headers is not None:
          try:
              return json.loads(headers)
          except Exception as exc:
              raise ValueError(
                  """Failed to parse headers into JSON.
                  Expected format: {{"KEY": "VALUE"}}, got {}, {}""".format(
                      headers, exc
                  )
              )
      return None
  
imports: import json
  import os
  import sys
  import pprint
  import time
  from subprocess import list2cmdline
  from typing import Optional, Tuple, Union, Dict, Any
  import click
  import ray._private.ray_constants
  from ray._private.storage import _load_class
  from ray._private.utils import get_or_create_event_loop
  from ray.autoscaler._private.cli_logger import add_click_logging_options, cf, cli_logger
  from ray.dashboard.modules.dashboard_sdk import parse_runtime_env_args
  from ray.job_submission import JobStatus, JobSubmissionClient
  from ray.dashboard.modules.job.cli_utils import add_common_job_options
  from ray.dashboard.modules.job.utils import redact_url_password
  from ray.util.annotations import PublicAPI
  from ray._private.utils import parse_resources_json, parse_metadata_json
label_desc: Use image node_id 2 for calling a global function with example usage: _handle_headers(headers) and returns: None, json